This invention relates generally to gas turbine engine regenerator assemblies and, more particularly, to improvements in cross arm sealing between low pressure hot exhaust and high pressure heated air passages at the regenerator disc.
In gas turbine engines, overall efficiency is improved by transferring heat from engine exhaust gas to incoming pressurized air. This is typically effected through a perforated regenerator disc rotatably supported on the engine block and intersecting both the exhaust gas passage and the pressurized air passage. The regenerator disc is heated as it passes through the exhaust gas passage and is cooled as it passes through the air passage, the incoming pressurized air then being heated by the disc prior to further temperature increase in the combustor. The success, in terms of engine performance and efficiency, of such regenerator arrangements depends, at least in part, on the success achieved in minimizing leakage between the exhaust gas passage and the incoming air passage at the inboard side of the regenerator disc where the passages are juxtaposed and convey both pressurized air and exhaust gas at high temperatures. The engine block partition separating the pressurized air and exhaust gas passages at the regenerator disc is typically called a cross arm and numerous cross arm seals have been proposed to maintain gas and air separation at the cross arm. A new and improved cross arm seal assembly according to this invention represents an improvement over heretofore known cross arm seals and is particularly adapted for maintaining both seal integrity in the presence of thermal distortion and effective seal cooling.